By colliding some of these beams, the physicists at the Large Hadron Collider hope to recreate the intense conditions just after the big bang and to solve other scientific riddles, such as the nature of dark matter, the invisible material that scientists think makes up most of the universe's mass.

Prior to the December shutdown, the Large Hadron Collider had set a new world record in high-energy physics by accelerating two beams of proton particles to 1.8 tera (trillion) electron volts (TeV) each and smashing them together, for a combined collision energy of 2.36 TeV.

Toward Full LHC Potential

Scientists have even more ambitious plans for the round that began this past weekend.

The current schedule calls for operating the machine at a level that would result in collisions with the energy of 7 TeV (3.5 TeV per beam) until late 2011 or early 2012.

The Large Hadron Collider will then be shut down once again so superconducting hardware can be upgraded to support collisions of 14 TeV—the Large Hadron Collider's maximum operating energy.

The 2012 rest period should last about a year, though the LHC team is "still looking at the planning of this shutdown, to try to devise ways of reducing its length," said Paul Collier, head of the beams department at CERN.

"God Particle" Proof Possible, Even at Half Power?

Even though the Large Hadron Collider won't be operating at its full potential, there are still plenty of exciting scientific discoveries that could be made, said Dan Green, a particle physicist at Fermilab in Illinois and a member of the Large Hadron Collider's Compact Muon Solenoid experiment.

"The energy increase matters," Green said. "At 7 TeV we open up new physics searches at high masses."

Even at half power, the LHC could yield evidence backing up the theory of supersymmetry, which says all the particles we know have more massive, but as yet undetected, partners, Green said.

The collider, he said, could also uncover "states reflecting large extra dimensions" beyond the three we know: the first (often represented by a line), second (a plane), and third (a cube).

Extra dimensions are predicted by string theory, an unproven concept that suggests that subatomic particles operate like tiny vibrating cords.

Evidence for the Higgs boson, which physicists think is responsible for mass in the universe, might also be found at the Large Hadron Collider's lower energies, Green added.